MX2009001187A

MX2009001187A - Detachable needle syringe having reduced dead space.

Info

Publication number: MX2009001187A
Application number: MX2009001187A
Authority: MX
Inventors: Arrigo Christina Joy D; Eric Schiller
Original assignee: Becton Dickinson Co
Priority date: 2006-08-03
Filing date: 2007-08-02
Publication date: 2009-03-06
Also published as: WO2008019035A2; CN101743029A; ES2739458T3; CA2659176A1; BRPI0715356A2; WO2008019035A3; JP2010504106A; AU2007281997A1; CN101743029B; US20080033347A1; EP2097126A2; EP2097126B1; US20230263964A1; JP5289313B2; US20100049143A1; CA2659176C

Abstract

A syringe and detachable needle assembly having reduced dead space features includes an elongate syringe barrel having open distal end including a collar and a distally facing annular surface projecting inwardly from the collar. A needle assembly includes a hub having a proximally facing annular surface and an outwardly projecting annular sealing ring positioned distally from the surface. The needle assembly also includes a cannula having a lumen therethrough connected to the distal end of the hub. Structure is provided for engaging the hub to the barrel resulting in the annular surface of the barrel contacting the annular surface of the hub to form a primary seal between said barrel and said hub and the annular sealing ring contacting the collar to form a secondary seal between the barrel and the hub.

Description

SOLTABLE NEEDLE SYRINGE THAT HAS REDUCED DEAD SPACE FIELD OF THE INVENTION The present invention relates to syringes with removable needle assemblies. More particularly, the present invention relates to a syringe and needle assembly having a structure for systematically minimizing dead space in a syringe barrel while containing an effective seal between the syringe barrel and the needle assembly. BACKGROUND OF THE INVENTION Syringe assemblies designed for use with replaceable needle assemblies generally contain a luer-lock or smooth luer-type connector to secure the needle assembly to the syringe barrel. These connections are based on a syringe barrel tip of elongated frusto-conical shape that engages a frusto-conical shape in a needle cone with friction. The relatively small acute angle of the syringe tip, measured from the longitudinal axis of the syringe barrel, provides an excellent seal between the syringe tip and the cone. However, slight variations in the angle or diameter of the tapered surfaces of the syringe barrel and / or the needle cone produce large variations in the relative position of the needle needle with respect to the end of the cylinder and, therefore, variations in the dead space. The space inside from the tip of the cylinder and between the end of the tip of the ci¬ cylinder and the end of the cavity in the cone constitutes a dead space containing liquid that can not be supplied or the syringe.

In the case of expensive medications and immunity programs zation! of multiple patients, the medication lost in the dead space in single-dose syringes, multidose and pre-filled can be expensive. This is especially true in immunization schedules that involve thousands of people. Minimizing dead space may result in more people being immunized with the same amount of immunization. medication provided for the program.

The prior art also describes a gasket flat, perpendicular to the longitudinal axis of the cylinder of je¬ ringa coupling with a flat seal in the cone of needle p > for use with a cylinder latching structure and Threaded needle set. The flat sealing gasket reduces in¬ Therefore, the portion of the dead space attributable to variations in the tolerances of the cylinder and the cone is largely determined.

However, imperfections on one or both surfaces flat 'coupling can lead to a seal with esca pes who lets medication out of the syringe during use. Although the prior art discloses many needle cone and syringe barrel connection structures, a low dead space syringe is still needed that is easy to manufacture and systematically provides the syringe with a small syringe dead space and an effective seal between the needle assembly and the syringe cylinder. COMPENDIUM OF THE INVENTION A detachable syringe and needle assembly having reduced dead space characteristics includes an elongated syringe barrel having a longitudinal axis, an interior surface defining a chamber for holding fluid, an open proximal end, an open distal end including a ring and an annular surface, preferably flat, which faces di- etally and protrudes into the ring. A portion of the ring includes an axially aligned circular side wall of cylindrical shape. A needle assembly includes a cone and a cannula. The cone includes a body portion having a proximal end, a distal end, a conduit therethrough, a preferably flat annular surface that looks proximally on the body portion contacting the annular surface of the cylinder forming a seal primarjio between the cone and the cylinder. The cone further includes an annular sealing ring that protrudes outwardly engaging the axially aligned portion., of cylindrical shape, of the side wall of the ring forming a secondary hermetic seal between the cone and the cylinder. The needle assembly further includes a cannula having a distal end, a proximal end and a lumen therethrough. The proximal end of the cannula is connected to the distal end of the cone so that the lumen of the cannula is in fluid communication with the ca-mara in the cylinder. A structure for releasably hooking the cone to the ring is also provided. The syringe assembly may also include an elongate plunger rod having a proximal end, a distal end and a stop at the distal end of the plunger rod. The stop is placed in fluid-tight engagement with the inner surface of the cylinder to move fluid from the chamber through the cannula by the relative movement of the plunger rod with respect to the cylinder. The stop may include a protrusion that looks distally to partially occlude the duct in the cone when the stop is in its most distal position within the cylinder. The annular sealing ring projecting outwards can be any structure that is sufficiently elastic for the deflection of the needle assembly in the cylinder so that the annular sealing ring deviates from contact with the circular portion of the side wall aligned axially, cylindrically, of the ring. The annular sealing ring may be an elastomeric O-ring preferably placed in an annular groove in the cone. The O-ring preferably has a circular cross section. The annular sealing ring may also be a tapered projection having a base adjacent to the body portion of the cone and a free end where the tapered projection is wider at its base than at its free end. The annular sealing ring may also be a cantilevered protrusion projecting radially outwards. This projection may be placed between two annular grooves in the cone. In addition, the annular sealing ring can be formed integrally with the body portion of the cone. An elongated hollow needle shield having a distillate end and an open proximal end can be extendable to the cone so that the needle shield covers the cannula. A needle assembly may include a cone and cannula that are integrally formed with thermoplastic material. The cannula can also be formed of metal such as stainless steel. and connect mechanically to the cone. The cannula may have a sharp distal tip or a blunt distal tip. The structure for releasably engaging the cone to the ring may include at least one thread in the ring or in the cone. The at least one thread can be a right thread and / or a thread of Figure 6 is a cross-sectional view of the needle assembly of Figure 5 taken along lines 6-6. Figure 7 is an enlarged partial cross-sectional view of the distal end of the cylinder of Figure 4. Figure 8 is a partial cross-sectional view illustrating the needle assembly connected to the syringe barrel. Figure 9 is an alternative embodiment of the assembly. of needle of the present invention having an integrally formed sealing ring. Figure 10 is a side elevational view of another embodiment of the needle assembly of the present invention. Figure 11 is an enlarged cross-sectional view of the distal end of the cylinder for use with a needle assembly of Figure 10. Figure 12 is a partial cross-sectional view illustrating the needle assembly of Figure 10 connected to the cylinder of Figure 11. DETAILED DESCRIPTION Although this invention may be practiced in embodiments in many different forms, the drawings are depicted and detailed embodiments will be described herein.

Preferred embodiments of the invention, it being understood that the present description is to be considered exemplary of the principles of the invention and it is not intended to limit the invention to the illustrated embodiments. The scope of the invention will be measured by the appended claims and their equivalents. With reference to Figures 1-2, a prior art syringe assembly 20 includes a cylinder 21 having an elongated body 22 that defines a chamber 23 for retaining fluid! The cylinder includes an open proximal end 25 and a distal end 26 including a tip 27 having a passage 28 therethrough in fluid communication with the chamber. The distal end of the cylinder may also include a luer lock ring 29 concentrically surrounding the tip 27. The luer ring has an internal thread 31. A needle assembly of the prior art 32 includes a cannula 33 having a proximal end 34, a distal end 35 and lumen 37 therethrough. A cone 38 includes an open proximal end 39 containing a cavity 40 and a distal end 41 attached to the proximal end 34 of the cannula so that the lumen of the cannula is in fluid communication with the I cavity in the cone. The needle assembly is extra-tightly connected to the syringe through friction engagement of the inner surface of the cavity in the cone and the outer surface of the tip 27. The cone also includes radial projections 43 at its proximal end to engage the thread 31 in order to hold the needle assembly fixedly to the cylinder. The prior art syringe assembly further includes an elastic stop 44 connected to an elongate piston rod 45. The liquid present in a syringe barrel can experience very high pressures during the injection process. This is especially true in the case of high viscosity medicaments and / or a needle cannula having a lumen of a smaller diameter. To seal the interface between the needle cone and the syringe against these high pressures, a frusto-conical engaging surface 30 at the tip 27 frictionally engages a frusto-conical foriha engaging surface 42 in the cone cavity 40. When the diameter of the engaging surface 42 is at the small end of its tolerance range and the diameter of the hook surface 30 of the cylinder tip is at the large end of its tolerance range, it can be seen that the tip of the cylinder not It will enter much into the cavity of the needle cone thus leaving more empty space in the cone cavity. Although the hermetic seal created by the coupling surfaces in a frustoconical way is very effective, the components they must be designed to accept all anticipated tolerance variations of the cylinder tip and cone cavity so that the distance the cylinder engages in the cone cavity will vary throughout the tolerance range, thus varying the amount of unobstructed space in the cone cavity. As can be seen in Figure 2, the dead space includes the unoccluded space in the tip passage 28, inherent in the smooth luer connection design, and the non-occluded space in the cone cavity 40, which partially require variations in tolerance. The non-occluded space in the cylinder tip is inherent to the design while the space occluded in the cone cavity will vary widely according to the tolerance variation properties of the luer-type latch. Accordingly, the dead space is difficult to control in the prior art syringe using luer-type connectors. Other prior art syringe assemblies have attempted to minimize and reduce the dead space variability by providing frusto-conical engaging surfaces that are at much greater angles to the longitudinal axis of the cylinder in order to shorten the variation in space. dead based on tolerances. You can achieve the best control of dead spaces with a surface cie de! flat coupling placed approximately at an angle 90 ° with respect to the longitudinal axis of the cylinder. This configuration better controls the dead space produced by variation of tolerance, and can overcome the dead space inherent in the luer connection cylinder tip. However, imperfections in mating surfaces or variations in the flatness of these surfaces can result in a tight seal between the cone and the cylinder that may have leaks initially or over a period of time, in addition, the quality of the closure Hermetic is directly linked with the amount of force applied to the cone while it is hooked on the cylinder. With reference to Figures 3-8, a detachable syringe and needle assembly 47 of the present invention, having features of reduced dead space, includes an elongate shaft: 49 having a longitudinal axis 50, an inner surface 51 which defines a chamber 52 for retaining fluid. Cylinder 49 further includes an open proximal end 53, an open distal end 55 including a rim 56 having a needle cone engaging structure and an annular surface 58 that faces distally and protrudes into the rim. The annular surface 58 is preferably flat. A portion of the ring includes a side wall axially aligned circular, cylindrical shape. A needle assembly 67 includes a cone 68 having a body porcicle 69 including a proximal end 70, a distal end 71 and a conduit 73 therethrough. An annular surface that looks proximally 74 in the body portion contacts the annular surface in the cylinder forming a primary seal between the cone and the cylinder. The annular surface 74 is preferably flat. The cone also includes an annular sealing ring projecting outwardly 75 sealingly engaging the circular side wall of the ring forming a secondary seal between the cone and the cylinder. In this embodiment, the annular sealing ring is an O-ring contained in the annular groove 76 around the body portion of the cone. As will be more fully explained below, the annular sealing ring projecting outwardly can be any structure that is sufficiently resilient to deviate to the installation of the needle assembly in the cylinder so that the annular sealing ring deviates from the sealing ring. on contact with the circular portion of the lateral wall of the arc. All these structures are within the scope of the present invention. The O-ring and other sealing ring structures described here are simply representative of these many possibilities. ?? The needle assembly further includes a cannula 96 having a proximal end 97, a distal end 98 preferably having a sharp distal tip 95 and a lumen 99 therethrough. The proximal end of the cannula is connected to the distal end of the cone so that the lumen is in fluid communication with the chamber in the cylinder. The cannula can be formed integrally with the cone, for example by injection molding, using thermoplastic materials or it can be formed separately, as in this embodiment, and joined to the cone. In this embodiment, adhesive 77 is used to join the cannula to the cone, and the cannula is made of metal, preferably stainless steel. A structure is provided for releasably engaging the cone to the ring including a cone engaging structure on the rim and a complementary loop engaging structure on the cjone. In this embodiment, the structure for releasably engaging the cone and ring includes at least one thread 57 on an inner surface 61 of the circular side wall 59. The thread may be clockwise or counterclockwise, and may also be a thread of multiple threads. The cone includes at least one thread that engages the projection. In this embodiment, there are two thread engaging projections 78, pre- 58 of the cylinder to form the primary protector between the cone and the cylinder. In this position, the annular sealing ring projecting outwards 75 is flexed as illustrated in figure 8 to form a secondary seal in¬ between the cone and the cylinder. The secondary seal is a hermetic seal of reserve in case of imper¬ Fections or other discontinuities on the surfaces or other factors that jeopardize your ability to sealed or in case the user does not produce enough rotational torque while connecting the cone to the cylinder to properly engage the primary seal.

It should be noted that the annular surface that looks coming soon 74 when it is flat in the cone and the surface ring that looks distally 58 when it is flat on the cylinder, does not have to be exactly aligned at 90 ° of the shaft I longitudinal It will work a wide range of angles, wishes taking the angles from 88 ° to 92 ° and preferring an angle of 90 °.

Figure 9 illustrates an alternative embodiment of the needle assembly of the present invention. In this embodiment, Needle set 167 works the same as the set Figure 3-8 needle. In this embodiment, the cone 168 has an annular sealing ring projecting outwards 175 gives for use with fluid transfer devices that They have a partition and other transfe¬ devices rencia of fluids designed to accept a blunt cannula.

An elongate cylinder 249 includes an interior surface 251 defining a chamber 252 and an open distal end 255 and a rim 256. The rim includes an interior surface 261 that It has less chili than a threaded hook. In this embodiment there are two thread engaging projections 262 facing i towards the left to engage the thread 281 in the cone 268. components of this realization work the same as the real¬ Figure 3-8. In this embodiment, the surface flat annular that looks next 274 in the cone hooks the flat annular surface that looks distally 258 in the cilin-! dro to form the primary seal between the cone and the cylinder. The ring cantilever sealing ring that looks out 275 will be flexed by the inside surface 261 during installation to provide a hermetic seal secondary between the cone and the cylinder.

There are many ways to configure the cone and ring of the cylinder including a cone that has an additional skirt surrounding the ring of the syringe cylinder. With this construction, the exterior of the hoop can include at least one thread or at least one thread engaging protrusion while the The top of the cone skirt shall include the other of a thread or at least one thread engaging projection. The engagement between the cone and the ring, in all configurations, may include a thread or structure in the form of a thread in the cone and a thread or structure in the form of a thread in the ring. All of these structures fall within the scope of the present invention and the embodiments described above are simply representative of these many possibilities.

Claims

said cone so that said lumen is in communication from fluid with said chamber; and means for releasably attaching said ring to said ring, The syringe assembly of claim 1 where said annular surface that looks distally to said cylinder is plañía. The syringe assembly of claim 1 where said annular surface that looks next to said portion body is flat. 4. The syringe assembly of claim 1 includes going further an elongated piston rod having an ex¬ proximal end, a distal end and a stop at that end distal of said piston rod, said stop being slidably mounted in fluid-tight engagement with said inner surface of said cylinder to displace fluid (said chamber through said cannula by the relative motion). of said plunger rod with respect to said cylinder. 5. The syringe assembly of claim 4 where said stop includes a projection that looks distally to partially occlude said duct in said cone when said stop is in its most distal position inside said cylinder. 6. The syringe assembly of claim 1 where said annular sealing ring is an elastomeric O-ring. 7. The syringe assembly of claim 6 wherein said O-ring has a circular cross section. The syringe assembly of claim 1 wherein said annular sealing ring is a tapered projection having a base adjacent said body portion and a free end, said tapered projection being wider at said base than at said free end. The syringe assembly of claim 1 wherein said annular sealing ring is a cantilevered radial projection. The syringe assembly of claim 1 wherein said sealing ring or annular is placed between two annular grooves. 11.] The syringe assembly of claim 1 wherein said annular sealing ring is integrally formed with said body portion. The syringe assembly of claim 1 further comprising an elongated hollow needle shield having a distal end and an open proximal end extractably hooked to said cone so that said needle shield covers said cannula. said means for releasably attaching said cone to said ring include at least one thread on an inner surface of said ring. The syringe assembly of claim 16 wherein said at least one thread is a right hand thread. The syringe assembly of claim 16 wherein said at least one thread is a thread of multiple threads. 19. The syringe assembly of claim 1 wherein said means for releasably attaching said cone to said ring include at least one thread engaging projection on said cone. 20. The syringe assembly of claim 1 wherein said means for releasably attaching said cone to said ring include at least one thread on an outer surface of said cone. 2 i. The syringe assembly of claim 1 where said means for releasably attaching said cone to said At least one thread engaging protrusion in one inner surface of said hoop. 22. A set of syringe and detachable needle that has Features of reduced dead space including: an elongated syringe cylinder that has a long axis tudinal !, an interior surface that defines a camera for retain fluid, an open proximal end, a distal end open including a ring and a flat annular surface that It looks di sstally and protrudes into the ring, I a portion of said ring having a circular side wall align axially, cylindrically; a needle assembly including a cone that has a portion | of body including a proximal end, one end distal, a conduit through it, a flat annular surface that looks closely in said body portion contacting said flat annular surface of said cylinder forming a primary hermetic seal between said cone and said cylinder, said cone also including an annular sealing ring that protrudes outwardly sealingly engaging said wall circular side of said ring forming a hermetic seal secondary between said cone and said cylinder, including partially occlude said duct in said cone when said stop at its most distal position inside said cylinder.